There is known an image display apparatus fixed on the head or the face of a user who observes an image, that is, a head mounted display. The head mounted display has, for example, image display units for the left and right eyes, and is configured so as to control the sight and hearing in combination with a headphone. If it is configured so as to completely block the outside world when mounted on the head, the virtual reality feeling is increased during viewing. Furthermore, the head mounted display is capable of showing the left and right eyes a different video and presenting a 3D image if displaying an image having parallax to the left and right eyes.
This type of head mounted display forms a virtual image on the retina of the eye in order for the user to observe the image. Here, when an object is closer to the lens than the focal length, the virtual image is formed on the object side. For example, there has been proposed a head mounted display which forms an enlarged virtual image of a display image on the pupil of a user by disposing a wide viewing angle virtual image optical system in front of the pupil with a distance of 25 mm, and further disposing a display panel having an effective pixel range size of about 0.7 inch in front of the wide viewing angle optical system (for example, see Patent Document 1).
Furthermore, with this type of head mounted display, a user can observe an image obtained by cutting out a part of a wide angle image. For example, there has been proposed a head mounted display which enables a user to feel the reality of a wide angle image following the movement of the head of the user by attaching, to the head, a head movement tracking apparatus consisting of a gyro sensor or the like (for example, see Patent Documents 2 and 3). By moving a display region in the wide angle image so as to cancel the movement of the head detected by the gyro sensor, it is possible to reproduce an image following the movement of the head, and the user have experience as if looking out over a wide space.
In such a system which presents a wide angle image following the movement of the head of a user, if an original wide angle image is not an omnidirectional image, there is no image information to be displayed when the user turns the head to an angle exceeding the view angle of the image.
For example, there has been proposed a video audio reproducing apparatus which enables a user to view video and audio by mounting it on the head, and fixes a video and audio image localizing position with respect to the head at the time when the head rotates and the display area reaches the limit of the whole area of the video signal content (for example, see Patent Document 4).
However, with the movement of simply fixing the video of the screen, it is difficult for the user to intuitively understand whether the display area reaches the limit of the wide angle image or the screen is frozen by failure.